1. Field of the Invention
The present invention relates to a VCA-based lens driving device, and more particularly, to a VCA-based lens driving device that enables the auto-focusing (AF) and the optical image stabilization (OIS).
2. Description of the Prior Art
The optical image stabilization (OIS) with a common magnet scheme has been developed as a solution of anti-shaking for a conventional lens driving device. Driving two sets of coils, e.g. the auto-focusing (AF) coil and the OIS coils, with a common magnet set to adjust the lens assembly makes the lens driving device compact, and is thus getting widely applicable for enhancing the image quality. Nevertheless, it is found that such a conventional scheme may have some disadvantages.
For example, in the known lens driving device, the OIS coils formed with the coil plate are typically different in length and/or are asymmetric. Such difference or asymmetry leads to a yawing effect, which makes the lens assembly and the magnet rotate unintentionally. The rotating of the lens assembly and the magnet will make the displacement sensor fail to detect the displacement correctly, such that the lens driving device cannot enable the auto-focusing and mage stabilization. Besides, in order to realize the AF and OIS functions in a greater precision, the magnetic sensitivity of the OIS coil structure needs to be further improved.